For suprathermal electrons with energy substantially greater than the thermal energy of the ambient electrons with which they interact, it is appropriate to use a collisional cold-target energy loss rate [1]}, for which the penetration depth of electrons increases with energy. [2]} analyzed a set of extended coronal flare loops located near the solar limb, and were indeed able to account for the observed behavior of loop extent with photon energy \(\epsilon \)  in terms of a cold-target collisional model with an extended acceleration region. [3]} have extended this analysis technique to a study of the variation of loop size with electron energy \(E\) , in which the visibilities used to construct the electron flux images are obtained by regularized spectral inversion of the visibility data in the count domain [4]}.
